Title: Influence of PAO + ester oil formulations on gear micropitting and efficiency

Authors: Ramiro C. Martins; Jorge H.O. Seabra; Luís F. Moron

Addresses: INEGI, Campus FEUP, Rua Dr. Roberto Frias, 400 4200-465 Porto, Portugal. ' FEUP, Rua Dr. Roberto Frias, s/n, 4200-465 Porto, Portugal. ' Repsol Technology Center, Ctra de Extremadura, A-5 km 18., 28931 Móstoles, Madrid, España

Abstract: This work presents a study about the influence of three different oil formulations on the protection against gear micropitting and its influence on gear efficiency. The study deals with both aspects because a well-balanced product is necessary and its behaviour must be demonstrated in dedicated tests. The three industrial lubricants had PAO base oil blended with ester oil and different additive packages. FZG gear power loss tests were performed under a wide range of operating conditions. The results obtained were used to establish a qualitative comparison of the oils formulations. The influence of lubricant formulation on the average friction coefficient between gear teeth was evaluated using an energetic model of the FZG test gearbox. The lubricants gear micropitting protection was evaluated according to DGMK short micropitting test procedure. During tests, lubricant analysis, mass loss measurements, surface observation and topography measurements where performed to evaluate the micropitting evolution.

Keywords: lubricants; power loss; gear efficiency; gear micropitting; gears; poly-alpha-olefine; PAO; ester oil; oil formulations; friction coefficient.

DOI: 10.1504/IJSURFSE.2011.044280

International Journal of Surface Science and Engineering, 2011 Vol.5 No.4, pp.312 - 329

Available online: 14 Dec 2011 *

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